Investigation of emission polarization and strain in InGaN/GaN multiple quantum wells on nanorod epitaxially lateral overgrowth templates

Abstract

Non-polar (a-plane) InGaN/GaN multiple quantum wells (MQWs) on the GaN nanorod epitaxially lateral overgrowth templates with different nanorod height have been fabricated. The average in-plane strain in the InGaN MQWs has been determined from 2.73×10 -2 to 2.58×10 -2 while the nanorod height in templates increases from 0 to 1.7 μm. The polarization ratio of the emission from InGaN MQWs varies from 85 % to 53 % along with the increase of the GaN nanorod height. The reduction of polarization ratio has been attributed to the partial strain relaxation within the epitaxial structures as a result of growth on the GaN nanorod templates and the micro-size air-voids observed in the nanorod templates.

The role of indium composition in InxGa1−xN prestrained layer towards optical characteristics of EBL free GaN/InGaN nanowire LEDs for enhanced luminescence

“…9,10 However the Stark effect is not preferable as it causes notable spatial separation of the carrier wave functions. [11][12][13] From the past research, prestrained growth method plays a crucial role for improving the efficiency of GaN/InGaN multi-quantum wells (MQWs). 14 While depositing of the prestrain layers before the MQW, a tensile strain is created in the quantum barrier, 15 thus enhancing the incorporation of large sized indium atoms.…”

“…The strong piezoelectric polarization (PZ), along the c‐plane direction, induced by high lattice mismatch within GaN and InGaN layers causes the quantum‐confined Stark effect (QCSE) 8 which eventually causes reduction of device's efficiency (EQE) 9,10 . However the Stark effect is not preferable as it causes notable spatial separation of the carrier wave functions 11–13 …”